Security Issues and Solutions in Peer-to-Peer Systems for Realtime CommunicationsPeer-to-peer (P2P) networks have become popular for certain applications and deployments for a variety of reasons, including fault tolerance, economics, and legal issues. It has therefore become reasonable for resource consuming and typically centralized applications like Voice over IP (VoIP) and, in general, realtime communication to adapt and exploit the benefits of P2P. Such a migration needs to address a new set of P2P-specific security problems. This document describes some of the known issues found in common P2P networks, analyzing the relevance of such issues and the applicability of existing solutions when using P2P architectures for realtime communication. This document is a product of the P2P Research Group. This document is not an Internet Standards Track specification; it is published for informational purposes.